Which protocol relies on XML for communication in Cisco SD-WAN?

The protocol that relies on XML for communication in Cisco SD-WAN is NETCONF. This protocol is designed to facilitate the management and configuration of network devices in a programmable manner. By using XML, NETCONF allows for structured and hierarchical data representation, making it suitable for configuration tasks.

NETCONF operates over a transport layer protocol like SSH, which provides a secure channel for communication. This is particularly important in SD-WAN environments where secure, remote management of devices is critical. The use of XML allows for the model-driven approach, meaning that network configurations can be expressed in a structured format which can be easily manipulated and validated. This capability is essential for automating network management tasks, which is a key aspect of modern network operations.

While the other protocols mentioned—BGP, OSPF, and RIP—are important routing protocols used for exchanging routing information within and between networks, they do not utilize XML for their operation. BGP (Border Gateway Protocol), OSPF (Open Shortest Path First), and RIP (Routing Information Protocol) focus on dynamic route discovery and maintenance rather than on network configuration management as NETCONF does. Thus, NETCONF stands out as the correct choice for a protocol using XML within Cisco's SD-WAN architecture.